The present invention relates to fibre-implanted nonwoven fabric comprising a combination of short fibres and a stretchy and elastic foamed sheet, and particularly to fibre-implanted nonwoven fabric in which these short fibres are not only mutually entangled on at least one surface of the foamed sheet but also interlocked with material of the foamed sheet along the surface and in the interior of said foamed sheet. The present invention relates also to a method for production of such fibre-implanted nonwoven fabric.
Single component nonwoven fabric made of fibrous web is so poor in its elasticity and stretchiness that such single component nonwoven fabric is not suitable at all as material for the product adapted, in use, to be pressed against or held to skin of human body. On the other hand, a stretchy and elastic foamed sheet, although preferred in said properties, is also unsuitable as material for the product to be used in direct contact with skin of human body, because such sheet has no comfortable fabric touch.
It is well known to implant extremely short fibres on a surface of a foamed sheet by so-called electrostatic implantation method or to laminate a fibrous layer comprising, for example, a fibrous web or cloth integrally to the surface of such foamed sheet with interposition of adhesive or directly by fusion so that the surface of this sheet may be bestowed with the fabric touch. However, the sheets thus obtained by the conventional methods have always been disadvantageous in that the layer of the foamed sheet itself and the fibrous layer have their characteristics too clearly distinguished from each other, since the fibres are merely laminated on the foamed sheet and that the initial elasticity of the foamed sheet itself is substantially maintained in the direction of the thickness thereof but can not be free from a serious deterioration in the superficial direction, since the fibrous layer is fixed thereto by adhesive or fusion. In consequence, no multiplicative effect is obtained from a combination of these two components in the sheet of prior art and such sheet is not suitable as material for the products as previously mentioned. Use of the sheet of prior art is, therefore, strictly limited. Particularly, the sheet of prior art utilizing adhesive is unsuitable as material for the products adapted to be used in direct contact with skin of human body from a medical viewpoint.
To obtain a novel product of this type which should be able to overcome the above-mentioned drawbacks, the inventors conducted various studies and found that the desired product is obtained when short fibres are implanted on an elastic foamed sheet by high energy treatment with water jet streams without use of any particular substance such as adhesive or binder or particular means such as fusion. The present invention is based on this observation.
According to the present invention, as has been described hereinabove, the short fibres of desired length and basic weight are implanted, without any particular adhesive or binder, on the stretchy and elastic foamed sheet from the surface into the interior thereof to provide nonwoven fabric in which said short fibres are not only mutually entangled on said surface but also interlocked with material of the foamed sheet at the level of said surface as well as in the interior of said foamed sheet in a complicated manner, so that said nonwoven fabric has a stretching elasticity substantially corresponding to that which is intrinsic to said foamed sheet and presents fabric appearance as well as touch on its surface. Furthermore, the nonwoven fabric according to the present invention is practically free from the inconvenience that said short fibres might easily fall off said foamed sheet. Accordingly, the nonwoven fabric according to the present invention can be advantageously used in practice as material for the products adapted to be, in their use, resiliently pressed against skin of human body. The method according to the present invention permits repeated use of the water jet streams for efficient treatment of the initial material to be treated and, in consequence, permits the nonwoven fabric of excellent properties as described above to be mass-produced at a reasonable low cost.